Splicing an image?

What I would like to do is take an image and then split it up into blocks of a certain dimension (say, 20x20). Then I would like to put these blocks into a 2D array. I tried searching for how to split images up, but got nowhere.

I had also this question before one month ago. but now it solved.
use Panel to stratch the image first is use BufferedImage to get the image then create one class which extends one JPanel and override one method named paintComponent to drow image on JPanel